We've been to the Royal Decameron numerous times.
Service overall has gone downhill, although especially at the lobby. If you need anything done with your room, just ask for a manager. Don't waste your time with the regular staff. Or talk to Freddie, one of the bell boys. He helped us out every time, told us who to talk to if we needed something, answered all our questions, etc. Also bring cash with you. They no longer exchange bills either. Lobby staff told to ask the serving staff to convert CAD to pesos, which is ridiculous. Not their job.
There's also a Walmart-type store about a 10-15 minute walk up the entry road if you need to buy anything.
The facility itself is great though, which is why we keep going back. Lots of pools, bars, restaurants, activities to do. The beach is massive and beautiful. And if beach volleyball is your thing, this is the place.
The entertainment/activities crews--orange shirts--are usually top notch. Lots of fun and funny games for guests and they were great with our kids. I got to know a few quite well--Gucxi, Danny, Himena and Jocelyn. Super fun, welcoming and helpful, and do a great job organizing games for the guests.
Maintenance crews, room cleaners, and bar staff are excellent. We had an obnoxious waiter at the buffet first night. The clown actually asked for a tip even though we had to get our own cutlery, etc. Servers are hit and miss nowadays, but we know the good ones by sight, so all good. But no service, no tip